GROWTH FACTOR CONTROL OF OVARIAN ANDROGEN BIOSYNTHESIS

在初步研究中，我们已经建立了腔前卵泡的GC分泌蛋白质的概念，这些蛋白质扩散到生长卵泡附近的间质室，具有刺激前膜细胞分化为内膜内分泌细胞的能力，这些细胞表达黄体生成素受体，并具有分泌雄激素的能力。这一过程发生时不需要黄体生成素。我们进一步证实，IGF-1和SCF的结合可以刺激不依赖于黄体生成素的雄激素的产生，其方式与腔前卵泡分泌的物质非常相似。最常见的生殖内分泌障碍是多囊卵巢综合征，其特征是卵巢膜细胞产生过多的雄激素，但刺激膜膜雄激素产生的机制尚不完全清楚。本研究的总体目标是明确IGF-I和SCF在正常发育卵泡膜分化和雄激素产生机制中的作用，并确定该机制是否可能参与PCOS的发病。为了实现这些目标，我们将使用我们独特的卵泡膜细胞分化模型来表征IGF-I和SCF在刺激卵泡膜促黄体生成素受体、P450/SCC、3β-HSD、P450/17αmRNAs和雄激素生物合成方面的相对重要性和相互作用。我们将研究IGF-1和SCF相互补充的分子机制，以诱导关键的类固醇生成和调节基因的表达，并激活膜细胞中的类固醇生成机制。我们将利用SCF基因具有各种特征突变的小鼠品系来检测这些突变导致的生殖缺陷的性质，以努力了解SCF在生殖功能和鞘分化中的作用。最后，我们将检测正常月经周期的大鼠和女性以及多囊卵巢综合征患者不同发育阶段卵泡中IGF-I和SCF的表达模式，以确定SCF+IGF-I的表达是否存在可能导致高雄激素血症和排卵功能障碍的变化。从这些研究中，我们将了解到有关独立于黄体生成素调节卵巢雄激素产生的新途径的重要信息。希望这将为开发治疗高雄激素血症的新疗法提供新的机会。

In preliminary studies we have established the concept that the GC of pre-antral follicles secrete proteins that diffuse into the stromal compartment adjacent to the growing follicles that have the capability of stimulating the differentiation of pre-theca cells into endocrine cells in the theca interna that express LH receptors and have the capacity to secrete androgens. This process occurs without the need for LH. We have further established that the combination of IGF-1 and SCF, both of which are known to be secreted by GC in pre-antral follicles, can stimulate androgen production independent of LH in a manner very similar to the substances secreted by pre-antral follicles. The most common reproductive endocrine disorder, polycystic ovary syndrome, is characterized by excessive androgen production by the ovarian theca cells but the mechanism stimulating thecal androgen production is incompletely understood. The overall goals of this proposal are to define the roles of IGF-I and SCF in the mechanism of theca differentiation and androgen production in normally developing follicles and to determine whether this mechanism could be involved in the pathogenesis of PCOS. To accomplish these goals we will use our unique model of differentiating ovarian thecal cells to characterize the relative importance and the interactions between IGF-I and SCF with respect to stimulating thecal expression of LH receptor, P450/SCC, 3beta-HSD, P450/17alpha mRNAs and androgen biosynthesis. We will examine the molecular mechanisms by which IGF-1 and SCF complement each other to induce the expression of the key steroidogenic and regulatory genes and activate the steroidogenic machinery in theca cells. We will use strains of mice that have various well-characterized mutation in the SCF gene to examine the nature of reproductive defects caused by the mutations in an effort to understand the role of SCF in reproductive function and thecal differentiation. Finally, we will measure the expression patterns of IGF-I and SCF in follicles at different stages of development in both rats and women with normal menstrual cycles and women with polycystic ovary syndrome to determine if there are alterations in SCF+IGF-I expression that could contribute to hyperandrogenism and ovulatory dysfunction. From these studies we will learn important information regarding a novel pathway regulating ovarian androgen production independent of LH. It is hoped that this will provide novel opportunities for developing new treatments for hyperandrogenism.